a. Field of the Invention
The present invention relates to a control unit for an internal combustion engine, and more particularly to a control unit for properly controlling the internal combustion engine by using a neural network.
b. Related Background Art
In the prior art, when fuel is to be supplied to an engine by a fuel injection system, one fuel injection valve is usually provided for each cylinder of the engine, an appropriate injection time for each fuel injection valve is set in accordance with the operation status of the engine, and the fuel injection valve is opened over the preset injection time to control the fuel supply amount.
Since the flow rate characteristic of each fuel injection valve inherently includes variance, the actual amount of fuel supplied may significantly differ from cylinder to cylinder even if the same fuel injection time is set for each of the fuel injection valves. As a result, fuel consumption and exhaust gas characteristic are deteriorated. In order to mitigate this problem, the prior art method groups fuel injection valves having similar flow rate characteristics for use in the cylinders of one engine.
However, according to this background art method, it is necessary to test all injection valves during their manufacture and to sort them into groups having similar flow rate characteristics. This process takes much time and manpower and results in a cost increase. Further, it is not possible under the prior art method to compensate for changes in the flow rate characteristics due to aging after shipment.